/*
** $Id: ltablib.c,v 1.38 2005/10/23 17:38:15 roberto Exp $
** Library for Table Manipulation
** See Copyright Notice in lua.h
*/


#include <stddef.h>

#define ltablib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


#define aux_getn(L,n)	(luaL_checktype(L, n, LUA_TTABLE), luaL_getn(L, n))


static int 
foreachi (lua_State *L) 
{
	int i;
	int n = aux_getn(L, 1);
	luaL_checktype(L, 2, LUA_TFUNCTION);
	for (i=1; i <= n; i++) 
	{
		lua_pushvalue(L, 2);  /* function */
		lua_pushinteger(L, i);  /* 1st argument */
		lua_rawgeti(L, 1, i);  /* 2nd argument */
		lua_call(L, 2, 1);
		if (!lua_isnil(L, -1))
			return 1;

		lua_pop(L, 1);  /* remove nil result */
	}
	return 0;
}


static int
foreach (lua_State *L)
{
	luaL_checktype(L, 1, LUA_TTABLE);
	luaL_checktype(L, 2, LUA_TFUNCTION);
	lua_pushnil(L);  /* first key */
	while (lua_next(L, 1)) 
	{
		lua_pushvalue(L, 2);  /* function */
		lua_pushvalue(L, -3);  /* key */
		lua_pushvalue(L, -3);  /* value */
		lua_call(L, 2, 1);
		if (!lua_isnil(L, -1))
			return 1;
		lua_pop(L, 2);  /* remove value and result */
	}
	return 0;
}


static int 
maxn (lua_State *L) 
{
	lua_Number max = 0;
	luaL_checktype(L, 1, LUA_TTABLE);
	lua_pushnil(L);  /* first key */
	while (lua_next(L, 1)) 
	{
		lua_pop(L, 1);  /* remove value */
		if (lua_type(L, -1) == LUA_TNUMBER) 
		{
			lua_Number v = lua_tonumber(L, -1);
			if (v > max) max = v;
		}
	}
	lua_pushnumber(L, max);

	return 1;
}


static int 
getn (lua_State *L) 
{
	lua_pushinteger(L, aux_getn(L, 1));
	return 1;
}


static int
setn (lua_State *L) 
{
	luaL_checktype(L, 1, LUA_TTABLE);
#ifndef luaL_setn
	luaL_setn(L, 1, luaL_checkint(L, 2));
#else
	luaL_error(L, LUA_QL("setn") " is obsolete");
#endif
	lua_pushvalue(L, 1);
	return 1;
}


static int 
tinsert (lua_State *L) 
{
	int e = aux_getn(L, 1) + 1;  /* first empty element */
	int pos;  /* where to insert new element */
	switch (lua_gettop(L)) 
	{
	case 2:  /* called with only 2 arguments */
		{ 
		pos = e;  /* insert new element at the end */
		break;
			}
	case 3:
		{
		int i;
		pos = luaL_checkint(L, 2);  /* 2nd argument is the position */
		if (pos > e) e = pos;  /* `grow' array if necessary */
		for (i = e; i > pos; i--) /* move up elements */
		{  
			lua_rawgeti(L, 1, i-1);
			lua_rawseti(L, 1, i);  /* t[i] = t[i-1] */
		}
		break;
			}
	default: 
		{
		return luaL_error(L, "wrong number of arguments to " LUA_QL("insert"));
			 }
	}
	luaL_setn(L, 1, e);  /* new size */
	lua_rawseti(L, 1, pos);  /* t[pos] = v */

	return 0;
}


static int 
tremove (lua_State *L) 
{
	int e = aux_getn(L, 1);
	int pos = luaL_optint(L, 2, e);
	if (e == 0) return 0;  /* table is `empty' */
	luaL_setn(L, 1, e - 1);  /* t.n = n-1 */
	lua_rawgeti(L, 1, pos);  /* result = t[pos] */
	for ( ;pos<e; pos++)
	{
		lua_rawgeti(L, 1, pos+1);
		lua_rawseti(L, 1, pos);  /* t[pos] = t[pos+1] */
	}
	lua_pushnil(L);
	lua_rawseti(L, 1, e);  /* t[e] = nil */

	return 1;
}


static int
tconcat (lua_State *L) 
{
	luaL_Buffer b;
	size_t lsep;
	int i, last;
	const char *sep = luaL_optlstring(L, 2, "", &lsep);
	luaL_checktype(L, 1, LUA_TTABLE);
	i = luaL_optint(L, 3, 1);
	last = luaL_opt(L, luaL_checkint, 4, luaL_getn(L, 1));
	luaL_buffinit(L, &b);
	for (; i <= last; i++) 
	{
		lua_rawgeti(L, 1, i);
		luaL_argcheck(L, lua_isstring(L, -1), 1, "table contains non-strings");
		luaL_addvalue(&b);
		if (i != last)
			luaL_addlstring(&b, sep, lsep);
	}
	luaL_pushresult(&b);

	return 1;
}



/*
** {======================================================
** Quicksort
** (based on `Algorithms in MODULA-3', Robert Sedgewick;
**  Addison-Wesley, 1993.)
*/


static void 
set2 (lua_State *L, int i, int j)
{
	lua_rawseti(L, 1, i);
	lua_rawseti(L, 1, j);
}

static int
sort_comp (lua_State *L, int a, int b)
{
	if (!lua_isnil(L, 2))	 /* function? */
	{ 
		int res;
		lua_pushvalue(L, 2);
		lua_pushvalue(L, a-1);  /* -1 to compensate function */
		lua_pushvalue(L, b-2);  /* -2 to compensate function and `a' */
		lua_call(L, 2, 1);
		res = lua_toboolean(L, -1);
		lua_pop(L, 1);
		return res;
	}
	else  /* a < b? */
		return lua_lessthan(L, a, b);
}

static void 
auxsort (lua_State *L, int l, int u) 
{
	while (l < u)	 /* for tail recursion */
	{ 
		int i, j;
		/* sort elements a[l], a[(l+u)/2] and a[u] */
		lua_rawgeti(L, 1, l);
		lua_rawgeti(L, 1, u);
		if (sort_comp(L, -1, -2))  /* a[u] < a[l]? */
			set2(L, l, u);  /* swap a[l] - a[u] */
		else
			lua_pop(L, 2);
		if (u-l == 1) break;  /* only 2 elements */
		i = (l+u)/2;
		lua_rawgeti(L, 1, i);
		lua_rawgeti(L, 1, l);
		if (sort_comp(L, -2, -1))  /* a[i]<a[l]? */
			set2(L, i, l);
		else
		{
			lua_pop(L, 1);  /* remove a[l] */
			lua_rawgeti(L, 1, u);
			if (sort_comp(L, -1, -2))  /* a[u]<a[i]? */
				set2(L, i, u);
			else
				lua_pop(L, 2);
		}
		if (u-l == 2) break;  /* only 3 elements */
		lua_rawgeti(L, 1, i);  /* Pivot */
		lua_pushvalue(L, -1);
		lua_rawgeti(L, 1, u-1);
		set2(L, i, u-1);
		/* a[l] <= P == a[u-1] <= a[u], only need to sort from l+1 to u-2 */
		i = l; j = u-1;
		for (;;)	 /* invariant: a[l..i] <= P <= a[j..u] */
		{ 
			/* repeat ++i until a[i] >= P */
			while (lua_rawgeti(L, 1, ++i), sort_comp(L, -1, -2)) 
			{
				if (i>u) luaL_error(L, "invalid order function for sorting");
				lua_pop(L, 1);  /* remove a[i] */
			}
			/* repeat --j until a[j] <= P */
			while (lua_rawgeti(L, 1, --j), sort_comp(L, -3, -1))
			{
				if (j<l) luaL_error(L, "invalid order function for sorting");
				lua_pop(L, 1);  /* remove a[j] */
			}
			if (j<i)
			{
				lua_pop(L, 3);  /* pop pivot, a[i], a[j] */
				break;
			}
			set2(L, i, j);
		}
		lua_rawgeti(L, 1, u-1);
		lua_rawgeti(L, 1, i);
		set2(L, u-1, i);  /* swap pivot (a[u-1]) with a[i] */
		/* a[l..i-1] <= a[i] == P <= a[i+1..u] */
		/* adjust so that smaller half is in [j..i] and larger one in [l..u] */
		if (i-l < u-i)
		{
			j=l; i=i-1; l=i+2;
		}
		else
		{
			j=i+1; i=u; u=j-2;
		}
		auxsort(L, j, i);  /* call recursively the smaller one */
	}  /* repeat the routine for the larger one */
}

static int
sort (lua_State *L) 
{
	int n = aux_getn(L, 1);
	luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
	if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
		luaL_checktype(L, 2, LUA_TFUNCTION);
	lua_settop(L, 2);  /* make sure there is two arguments */
	auxsort(L, 1, n);

	return 0;
}

/* }====================================================== */


static const luaL_Reg tab_funcs[] =
{
	{"concat",		tconcat},
	{"foreach",		foreach},
	{"foreachi",	foreachi},
	{"getn",		getn},
	{"maxn",		maxn},
	{"insert",		tinsert},
	{"remove",		tremove},
	{"setn",		setn},
	{"sort",		sort},
	{NULL,			NULL}
};


LUALIB_API int 
luaopen_table (lua_State *L) 
{
	luaL_register(L, LUA_TABLIBNAME, tab_funcs);
	return 1;
}

